In my ventures as a freelance writer, I've run into these scenarios quite a bit:
1) Website tells you that for a fee of x dollars per month, they'll give you access to thousands of freelance jobs. One site that I subscribed to for a month gave me access to maybe 20 jobs in a month. Talk about a tax write-off. There are legit sites out there, but this one wasn't one of them.
2) Other sites will give you work, but to get the work, you must pay a service fee per month. I pass on these and if ask, I'd say, "No, you don't understand: I don't pay you to work. You pay me."